Magnolia 'Little Gem'-easily controlled to te 2.5-3m height range that suits your requirements ben. Will generally form a clipped block of foliage over time though not as dense as the lilly pilly we chatted about. *Could be used as a "pleached" hedge(stripping the trunk of foliage and promoting foliage on the top half of the plant) so that a second tier of plant material can be included underneath for a more dynamic visual aesthetic.